Hello,
Here is the marriage certificate unfortunately doesn't give much to go on and the lack of imagination in the names doesn't help either.
17 August 1918 @ Penuel Calvanistic Methodist Chapel, Duffryn Street, Ferndale, Rhondda.
John Jones 36yrs Widower - Collier - 28 Church Street, Ferndale - John Jones (deceased)
Hannah Davies 24yrs Spinster - no occu - 20 Beech Street, Ferndale - William Davies (deceased)
Witnesses: Charles Davies & Thos E Horgan
Minister: Benjamine watkins
I've searched the 1911 census for the addresses listed there was a John Jones living in 28 church street then but whether its the same one I don't know.
From what I can gather John Jones was from the Llanddewibrefi area of Cardiganshire.
As for William Davies I have no idea.
Ant help appreciated?

Regards
Tony!!!